Two-dimensional photometric decomposition of the TeVBL lacertae objects Markarian 421, Markarian 501, and 1ES 2344+514

We have obtained high-resolution R-band images of three BL Lacertae objects , Mrk 421, Mrk 501, and 1ES 2344 + 514, that have been detected at high-ene rgy (TeV) gamma-rays. Because of their TeV emission, these three objects ha ve been targets of intensive optical monitoring during the last few years. We have studied the morphology of host galaxies by fitting ellipses and two -dimensional galaxy + core models to the observed surface brightness distri bution. We find the host galaxies to be large (effective radii 7-40 kpc) an d bright (M-R = -23.2 to -24.6) elliptical galaxies, whose surface brightne ss distribution can be described by a single power law I(r) proportional to r(-beta) with beta = 0.10-0.36 to an accuracy of similar to 0.2 mag. The i sophotes of the host galaxies are found to be ellipses with no apparent "bo xyness" or "diskyness." The host galaxies of Mrk 501 and 1ES 2344 + 514 als o exhibit a position angle twist that increases linearly with distance from the nucleus. Using the two-dimensional photometric decomposition we have constructed tab les of host galaxy magnitude as a function of measuring aperture diameter a nd seeing. These tables can be used to "clean" photometric data of the host galaxy contribution.